睾丸酮丛毛单胞菌对羊草根际土壤PAHs降解及细菌群落结构的影响

Effects of Comamonas testosteroni on PAHs degradation and bacterial community structure in Leymus chinensis rhizosphere soil

探究睾丸酮丛毛单胞菌(Comamonas testosteroni,C.t)联合羊草修复多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)污染土壤过程中,羊草根际土PAHs降解及根际微生物的变化。用气相色谱-质谱法(GC-MS)检测C.t联合羊草时根际PAHs的降解,通过高通量测序技术测定羊草根际土壤细菌群落及多样性,采用冗余分析及网络分析评价PAHs降解与细菌群落组分之间的相关性,用PICRUSt软件预测PAHs降解潜力。结果表明,C.t的接入在修复后期(60–120 d)促进PAHs降解,使羊草根际细菌丰富度、多样性以及细菌与PAHs的相关性发生改变,并且提高了羊草根际PAHs的降解潜力。C.t主要通过影响变形菌门属水平中鞘氨醇单胞菌(Sphingomonas)、MND1和Nordella,放线菌门属水平上红色杆菌(Rubrobacter)和Gaiella,酸杆菌门属水平中RB41以及拟杆菌门中黄杆菌(Flavobacterium),从而加快羊草根际土中萘(Nap)、菲(Phe)、苯并芘(BaP)3种PAHs的降解。研究以期为C.t联合植物降解土壤PAHs污染提供理论依据,为微生物联合植物修复土壤PAHs提供新的微生物选择。

To investigate the degradation of polycyclic aromatic hydrocarbons(PAHs)and the changes of rhizosphere microorganisms in the rhizosphere soil of Leymus chinensis during the remediation of PAHs contaminated soil by Comamonas testosteroni(C.t)-assisted Leymus chinensis,we evaluated the removal of PAHs in the rhizosphere of Leymus chinensis using gas chromatography-mass spectrometry(GC-MS),analyzed the bacterial community and the diversity in Leymus chinensis rhizosphere soil by high-throughput sequencing technology,characterized the correlation among PAHs degradation and bacterial community components performing redundancy analysis(RDA)and network analysis,and predicted PAHs degradation potential via PICRUSt software in this paper.The degradation of PAHs in the rhizosphere of Leymus chinensis was promoted,the abundance and diversity of bacteria and the correlation among bacteria and PAHs were changed,and the degradation potential of PAHs in Leymus chinensis rhizosphere soil was enhanced in the later stage of phytoremediation(60–120 d)due to the incorporation of C.t.The accelerated degradation of three PAHs(Nap,Phe,BaP)was accompanied by the differ abundance and correlation of Proteobacteria(Sphingomonas,MND1,Nordella),Actinomycetes(Rubrobacter,Gaiella),Acidobacteria(RB41)and Bacteroides(Flavobacterium)affected by C.t.The results provide new insight into the microorganism choices for microbial assisted plant remediation of soil PAHs and the mechanisms of enhanced PAHs degradation via the combination of Comamonas testosteroni engineering bacteria and plants.